Insulating-lining.



No. 784.695. PATENTED MAR. 14, 1905. N. MARSHALL.

V INSULATING LINING.

APPLICATION FILED APR.15, 1903.

//v l/E/V TOR 4 UNITED STATES Patented March 14, 1905.

PATENT OFFICE.

INSULATING-LINING.

SPECIFICATION forming part of Letters Patent No. 784,695, dat d March 14, 1905 Application filed April 15, 1903. Serial No. 152,714;

To all whom it 7nd, concern.-

Be it known that I, NORMAN MARSHALL, of Newton, in the county of Middlesex and State of Massachusetts, have invented certain new and useful Improvements in Insulating-Linings, of which the following is a specification.

The invention relates to insulating-sleeves such as are used in incandescent-lamp sockets .to separate the metallic outer shell from the current-carrying parts of the socket. It is desirable that sleeves of this character when used as linings for the outer shell should be retained in the outer shellwhen the parts are taken apart in wiring or for other purposes, and at the same time the lining should be so held in the shell that it may be quickly and readily removed when desired, as for the purpose of refinishing the shellthat is to say, the lining should be held in the shell in such a manner that it will not fall out when the shell is removed, but may be readily removed, if desired.

The insulating-linings Which have gone into practical use have heretofore been formed of insulating fiber tubing and have been shaped to fit the shell as perfectly as possible. Vith linings made of this fiber it has been found to be impractical to make the linings invariably fit the shell with just the requisite closeness to prevent the linings falling out and still allow of the ready insertion and removal of the linings. Moreover, if a lining under certain conditions fitted the shell with just the proper closeness it would not do so under the varying conditions as to moisture and temperature. With these linings, therefore, there is constant danger of the lining dropping outof the shell when the shell is removed, and this has been a recognized defect in this class of linings, and attempts have heretofore been made to remedy this defect without satisfactory results.

It is the object of this invention to provide an insulating-sleeve adapted for use in incandescent-lamp sockets which shall meet the practical requirements as to forming an efficient protection of the parts, and which when forming a lining for the outer shell will be retained in the shell at all times and under all conditions without danger of dropping out and without offering undue resistance to its removal. This I accomplish by forming an elastic insulating sleeve or lining having a portion of its periphery of larger diameter than the part of the shell within which it is to fit, so that as the lining is inserted in the shell this portion will be compressed and by its elasticity will maintain an effective holdingpressure' on the shell under all conditions. The lining may be made of any suitable insulating niateriaf having the requisite elasticity and adapted to be formed into the shape required to lit within the shells of the lampsockets.

I have discovered that elastic linings such as described may be formed from paper tubing consisting of closely-wound layers of paper by the action of suitable-formed dies which draws down the tube for a portion of its length, and that-the linings thus formed have the requisite elasticity and compressibility. I have also discovered that such paper linings will assume the proper shape when removed from the dies if the dies are shaped to give the lining when held by the dies a shape and size corresponding to the shape and size of the shell in which they are to be inserted. When the paper lining is released from the holding action of the dies, a portion of the reduced end will spring outward somewhat, thereby forming an elastic portion of a diameter somewhat larger than the diameter of the part of the shell in which it is to fit. hen the lining is inserted in the shell, this elastic portion is compressed to the size originally given it by the dies, and by reason of its tendency to expand will hold the lining in place. By reason of my discovery of these peculiar characteristics of a paper tube when subjected to the action of the shaping-dies I am enabled to produce a lining having an elastic holding portion at materially less expense than the fiber linings have been produced, and thereby produce a more eflicient and satisfactory lining and at the same time reduce the cost of manufacture.

In explaining more in detail the preferred form of my elastic lining and the method by which it is produced I will refer to the accompanying drawings, in which- Figure 1 is a sectional view showing the tube and the dies just before the dies begin to reduce the diameter of the tube. Fig. 2 is a similar view showing the tube shaped by the dies. Fig. 3 is a view showing the tube free from the action of the female die and partially removed from the male die. Fig. I is a sectional view of the completed lining, and Fig. 5 is a sectional view showing a lining partially inserted in a shell.

In forming the elastic lining from a paper tube the tube A, which consists of closelywound layers of paper closely compacted together, is subjected to the action of the dies B (l. I have discovered that a thin paper tube of the requisite diameter for a socketlining may be drawn down for a portion of its length by the action of dies similar to those used in drawing down fiber tubing if the fe male die is so shaped that the tube is confined throughout substantially its entire length during the action of the dies. I thus conline the tube by so forming the female die B that the part of larger diameter extends to the end of the tube A when the shoulder B begins to act on the tube. IVith the dies thus shaped the tube will be drawn to a smaller diameter a portion of its length as the female die is forced into the position of Fig. 2. The lining thus formed has an end portion A of larger diameter and a portion A of smaller diameter and is of a size and shape when held by the dies to lit within the metallic shell S. (Shown in Fig. 5.) \Vhen the female die is removed and the lining removed from the male die, the reduced portion A springs outward at A" near the shoulder A, as shown in Figs. 3 and 4, the dotted lines showing the shape of the lining when held by the dies. This portion A" forms an elastic and compressible holding portion, which is compressed as the lining is inserted into the shell, as shown in Fig. 5. This portion A' tends to expand owing to the elasticity of lining, and thereby holds the lining in place while admitting of its ready removal and insertion when desired.

I have not indicated the slots and openings usually formed in the linings for sockets, as

these will be made to suit the socket in which the lining is to be used. i

\Vhat I claim, and desire to secure by Letters Patent, is-

1. An insulating-lining consisting of a tube having end portions of different diameters and having an elastic and compressible portion of greater diameter than the part within which it is to fit, substantially as described.

2. An insulating-lining consisting of a tube having end portions ofdifferent diameters and having an elastic integral holding portion, substantially as described.

3. Aninsulating-liningconsisting ofan elastic compressible tube one end of which is of smaller diameter than the other, substantially as described.

4. An insulating-lining consisting of a tube having an.elastic compressible holding portion of greater diameter than the part within which it is to lit, substantially as described.

5. An insulating-lining consisting of a paper tube having its diameter reduced for a portionofitslength,substantiallyasdescribed.

6. An insulating-lining consisting of a paper tube having its diameter reduced for a portion of its length and having a portion of greater diameter than the part Within which it is to lit, substantially as described.

7. The combination with a metallic shell, of an insulating-lining consisting of an elastic compressible tube held frictionally against the shell by its resiliency, substantially as described.

8. An insulating-sleeve consisting of a tube NORMAN MARSHALL.

\Vitnesses:

FRANCES L. l/VOOD, E. M. CARPENTER.

Disclaimer in Letters Patent No. 784,695.

DISCLAIMER.

-Mass. INSULATING-LINING. Patent dated January 4, 1909, by the patentee.

784,695.-N0rman Marshall, Newton,

March 14, 1905. Disclaimer filed Enters this disclaimer To claims Nos. 5 and 9 of said Letters Patent, which are in the following words,

to wit:

5. An insulating-lining consisting of a paper tube having its diameter reduced for a portion of its length, substantially as described.

9. The combination with a metallic shell. of an insulating-sleeve consisting of an elastic, compressible paper tube held in frictional engagement with the shell by its own resiliency. [Ofiicial Gazette, January 12, 1.909.] 

